ORANIENBURG, GERMANY - APRIL 19: Petr Mischtschuk, who as a 14-year-old was imprisoned by the Nazis at the Buchenwald and later Sachsenhausen concentration camps during World War II, lays a flower at the Russian memorial marking the 70th anniversary of the liberation of Sachsenhausen on April 19, 2015. The Nazis ran Sachsenhausen from 1936-1945, using it initially for political prisoners, then later also for resistance fighters from across Europe, Soviet prisoners of war, Jews, homosexuals, Jehova's Witnesses and other victims; the camp included a gas chamber, execution pit and ovens for burning bodies, and an estimated 30,000 inmates died.